An example of the sliding part, which is used in the corrosive environment in liquid, is a sliding material forming a bearing that supports the rotating shaft in the casing of the motor fuel pump provided to the engine utilizing liquid fuel such as gasoline and light oil. In addition, as examples of the sliding material used in the corrosive atmosphere such as sea water and the snow melting agent, the sliding material for the outboard motor; and the exhaust throttle valve used for the diesel exhaust gas purification system, are known.
In addition, as examples of the sliding material used in the corrosive atmosphere of high temperature, exhaust gas, or the like, the exhaust throttle valve used for the diesel exhaust gas purification system; and the recirculation exhaust gas flow control valve of the EGR (Exhaust Gas Recirculation) type internal combustion engine, are known.
The engine that uses the liquid fuel such as gasoline and light oil with the motor fuel pump is used all over the world; and high wear resistance is demanded for the motor fuel pump. Qualities of liquid fuel vary worldwide depending on locations. Thus, depending on the locations, there is an area, in which bad quality gasoline with poor quality is used. Thus, corrosion resistance against the bad quality gasoline is needed for the sliding material of the bearing used for the motor fuel pump.
Conventionally, as an example of the bearing sliding material of this type of usage, the sliding material made of the sintered Cu—Ni-based alloy, which has the composition of Cu-21 to 35% Ni-5 to 12% Sn-3 to 7% C-0.1 to 0.8% P, is known (refer Japanese Patent No. 4521871 (B)).
In addition, as a sliding material used: in the high temperature corrosive atmosphere; and under the corrosive environment due to salt such as sea water and the snow melting agent, the sliding materials made of stainless or sintered alloy, which is subjected to a surface treatment such as nitriding, is known (refer Japanese Patent No. 5386585 (B)).
In addition, as a sintered sliding part having excellent corrosion resistance and wear resistance under the high temperature environment, the sintered sliding part, in which the amounts of Cu and Si are defined and boron nitride is added in a predetermined ratio, is known (refer Japanese Patent No. 5337884 (B)).